In 2019, a group of international researchers discovered fossilized footprints while analyzing animal track sites in South Korea. These fossil prints were discovered during excavation at the Sacheon Jahye-ri site near Sacheon City. They are from the Early or Lower Cretaceous period of the Mesozoic era and date back to 110-120 million years ago. The Mesozoic era is also referred to as the Age of Reptiles and the Age of Conifers.
The footprints of the Sacheon Jahy ri track site represent the first Asian occurrence. Their body length was estimated to be over 3 meters (10-foot) and the footprints measured around 24 centimeters (9.5 inches). The measurement of the footprint also suggests that the track-makers had legs with a height just like human adult legs. These fossil prints were found in muddy shores which were once inhabited in the Cretaceous period by frogs, lizards, turtles, and dinosaurs. The muddy shores helped in preserving a small portion of footprints which enable us to understand the various life forms of that period.
The track sites were originally thought of as one of an ancient animal pterosaur- a winged reptile and it was generally thought to have walked on all fours when on the ground. The absence of handprints and wing prints on the track site proved otherwise. Further research proved it to be of an early ‘two-legged’ or bipedal crocodile that belonged to Crocodylomorph species (crocodile relatives). The researchers named the fossil prints as Batrachopus grandis. (Fossil prints and fossilized trackways are given scientific names similar to animals)
The discovered Crocodylomorph tracks revealed the impressions of the toes, the pads on their feet bottom, and even occasional patches of the skin. It was also inferred that these creatures were more terrestrially adapted. Dr. Anthony Romilio a paleontologist and one of the study authors from the University of Queensland said that finding hundreds of Crocodylomorph tracks is generally deemed rare in Asia.
In the beginning, the researchers found footprints but no handprints on site which were puzzling as typical crocodiles of today are either ‘four-legged’ or quadruped. They also failed to find “overprinting” impressions which happens when a four-legged animal steps on the handprint with its hind feet while walking. Professor Kyung Soo Kim from the Chinju National University of Education in South Korea who led the research cleared that the present-day crocodiles walk in a squat stance and have wider trackways, but the ancient bipedal crocodile left narrow trackways. Back then, dinosaurs and their bird descendants walked on their toes, but crocodiles walk on their flat feet leaving clear impressions like humans. This evidences along with the lack of tail-drag marks indicate that they moved bipedally.
Footprints of similar have been discovered from older periods such as the Triassic period (251 -199 million years ago) and the Jurassic period (201.3 – 145 million years ago). It was believed that crocodylomorphs were dominant species during the Triassic period and walked on two legs similar to some dinosaurs. They became extinct at the end of the Triassic period, but the tracks discovered in Jinju Formation show that they lived long after the Triassic period.
In 2012, a set of less defined and younger indentations were discovered in the Haman Formation at Gain-ri in South Korea. They were believed to be of large pterosaurs, but the footprints found around the world show that they walked on all fours (when on the ground). The researchers concluded that the footprints at Gain-ri were pterosaurs, which moved bipedally in order to avoid their wings being dragged through the muck. Back then, the researchers quoted the footprints as “enigmatic”. The recent discovery of footprints from the Jinju Formation changes the perception of the “enigmatic” prints of 2012.
These spectacular fossils are naturally well preserved with even fine details of the toe-pads and scales on their soles. But, the acknowledgement of the creature’s existence relies mainly on the fossil prints found as no physical remains have been discovered.
Images Provided By Dr Anthony Romilio, Research Associate, UQ’s Dinosaur Lab
References: University of Queensland , Scientific Reports
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Nice article.
Very nice article.